updated alloc_endpoint to mutate a copy of the returned allocation, instead of the instance in the state store

command/agent/alloc_endpoint.go

@@ -127,6 +127,7 @@ func (s *HTTPServer) allocGet(allocID string, resp http.ResponseWriter, req *htt
 	alloc.SetEventDisplayMessages()
 
 	// Handle 0.12 ports upgrade path
+	alloc = alloc.Copy()
 	alloc.AllocatedResources.Canonicalize()
 
 	return alloc, nil